AES E-Library

AES E-Library

An Air-Cored Autotransformer with Nearly Equal Decibel Taps

When the first shunt inductor from the input of a passive high-pass filter, serving as a crossover element in a loudspeaker system, is realized as an autotransformer, the effective sensitivity of the driver that it feeds can be adjusted without changing its frequency or phase response or interacting with other parts of the system. It is shown how such a circuit element, which 1) uses an air core and 2) has taps in nearly equal steps of dB, may be realized economically.